A well known conventional filter for filtering fuel supplied to internal combustion engines contains an element inside a cylindrical housing. However, there is a need to provide a circular stay for installing such a conventional cylindrical filter. In addition, when a cylindrical fuel filter is installed on a vehicular body, the filter tends to greatly protrude from a surface where it is installed.
Accordingly, one prior proposal installs the fuel filter inside a fuel tank. For example, U.S. Pat. No. 5,392,750 discloses a ring-shaped fuel filter whose shape enables it to be installed on an outer periphery of a fuel pump.
However, one problem with the construction according to U.S. Pat. No. 5,392,750 is the enlargement of the diameter of the filter because it has to be installed on the outer periphery of the fuel pump.